The loading of trucks and railway cars with flowable solids from overhead supply bins or hoppers has long been an awkward and haphazard procedure involving much spillage of valuable material and the incomplete loading, overloading or uneven loading of the vehicles and rail cars. Such uneven loading and overloading can be particularly dangerous in the case of railway cars in a train and is also dangerous in the case of trucks causing instability and other problems pertaining to safe driving. The premises around the loading station is soon cluttered with overflow or waste solids requiring additional labor and economic loss due to frequent cleaning up operations.
It has long been recognized as desirable to provide some means for the orderly and controlled automatic or semi-automatic loading of vehicles with flowable solids to alleviate the above problems and economic losses, and in the prior art, some proposals have been offered to solve the problem but none has proven to be entirely satisfactory. One example of the patented prior art is disclosed in U.S. Pat. No. 3,666,119, issued May 30, 1972, to Ward H. Parsons. In this patent, a driver-operated truck approaches an overhead loading hopper having release gates for flowable solids. The truck driver manually positions a start-up switch assembly in accordance with a digital setting on a nearby graduated scale to properly position the elevations of a pair of load level sensing probes or tilt switches. Following this, the driver operates the start-up switch in response to which the overhead bin gates open and the loading of the truck takes place at the forward extremity of the load-receiving body. When the load of solids reaches a desirable level, the load level sensor is displaced or tilted to close the bin gates and activate a first signal light which tells the truck driver to advance the vehicle. As soon as the load level sensor returns to its normal vertical position, the signal light is extinguished so that the driver will stop the truck and the bin gates reopen to discharge another increment of the load into the truck body up to the level where the level sensor is again displaced and the driver's advance signal is reactivated. This cycle is repeated in the patent until the loading of the vehicle is completed back to the rear end of the load-receiving body, at which pont the truck tailgate displaces the second sensor or tilt switch, activating a green light telling the driver that the truck is fully loaded and to drive the truck away. The bin gates are held closed at this point.
While the patented arrangement of vehicle loading is a substantial advance in the art, the system is not entirely foolproof and therefore not completely satisfactory in terms of reliability and complete practicality, and therefore there continues to be a need for an even more improved and efficient loading apparatus and method for trucks, rail cars and the like.
It is the objective of the present invention to completely satisfy the requirements of the art for loading vehicles with flowable solids from an overhead source and, in so doing, to utilize to a great extent the load level sensing means, signalling means and automatic bin gate operating means of the prior patent. However, in so doing, the present invention has achieved a simplification of the apparatus in the prior patent by entirely eliminating one probe or tilt switch without any loss of the functional results obtained by two such probes in the patent. Additionally, and more importantly, this invention eliminates reliance on the human operator or driver of the vehicle to preset the load level sensor manually by a digital setting in relation to the known capacity of the vehicle or railway car. This manual operation, either by the driver or bin operator, requires first, an awareness of the digital setting number on the scale, and second, conscientiousness on the part of the driver or operator in the setting of the number so as not to overflow or overfill the vehicle. In many cases, such reliability on the part of human operators is not forthcoming and therefore the present invention eliminates the need for reliance on manual operation for the all-important positioning of the load level sensor or tilt switch probe. In the invention, such positioning takes place automatically without need for a human operator and is entirely in response to the operation of a sensing device which detects the presence of a truck or railway car at the loading station beneath the hopper, and in response to such detection activates a lowering means for an overhead second sensing device associated with the load level sensor, causing these two elements to descend together toward the vehicle load-receiving body.
When the second sensing device detects the top of the load-receiving body, the lowering means is deactivated and the load level sensor is stopped and positioned at the proper level to regulate the depth of loading of the vehicle so that no overloading or spillage of material can occur. From the point on, the mode of operation for completely loading the vehicle with flowable solids in several increments is carried out substantially in accordance with the teachings of U.S. Pat. No. 3,666,119. The disclosure of this patent, therefore, is relied upon as a part of the disclosure in this application and the patent is thus incorporated herein by reference for the sake of simplifying and minimizing the disclosure in this application.
Following the completion of vehicle loading in this invention and the movement of the vehicle beyond the first sensing device which has continued to sense the presence of the vehicle during the complete loading process, the first sensing device now detects the absence of the loaded vehicle and in response to this detection or sensing operation the load level sensor and the second sensing device coordinated with it are both returned automatically to their normal overhead positions well above the vehicle ready for the start of a subsequent loading cycle of operation when the next truck or railway car in a train approaches and is detected by the first sensing device, whereupon the abovedescribed cycle is repeated.
An added advantage of the invention over the prior art lies in the ability of the load level sensor to automatically reposition itself at different levels during the complete loadout of the vehicle in such cases where the load-receiving body of the vehicle is uneven in height or tapers toward the rear as is frequently the case with large trailer bodies. In such cases, the second sensing device associated with the load level sensor will continuously respond to the changes in silhouette of the vehicle body and continuously reactivate the raising and lowering means for the load level sensor and the second sensing device, whereby these elements are properly repositioned during advancement of the truck or vehicle to the several incremental loading positions.
Additionally, the present invention lends itself to a completely automated system in which trucks may be driven onto an automatic conveyor similar to conveyors found in automatic car washing facilities. In the invention, such a conveyor will advance the vehicle to the initial sensing position whereupon the automatic positioning of the load level sensor will take place exactly as previously described, as well as the incremental loading of the truck under regulation of the load level sensor. However, there will be no necessity for a driver to advance the vehicle during the incremental loading, responsive to a signal light or to an audible signal. Instead, the truck conveyor means will be periodically activated and deactivated to advance the truck properly for the several incremental loadings thereof in response to the operation of the load level sensor.
It is the intention in this invention not to be limited to the use of any particular form of sensing or detecting instrumentalities, or any particular form of raising and lowering means for the load level sensor. Various forms of these devices may be used. Also, the overhead source of flowable solids may be a bin or hopper with gates or may be a power-driven material conveyor of any practical type. Therefore, the particular apparatus to be described in detail is illustrative only of one practical embodiment of the invention and it should be understood that the details of apparatus may be varied and the essential method may be practiced with various forms of the apparatus shown schematically in the accompanying drawings.
Other features and advantages of the invention will become apparent during the course of the following detailed description.